People, would anybody of you have more data about the trials of the P-38 with torpedos? Hopefully, something above hangar talk

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It was a P-38F-13-LO (43-2035) originally built as an RAF Lightning II (AF221), and for the new F model, had two pylons under the wing that could handle external fuel tanks, 1,000 pound bombs or in this case, one 22" 1,900 pound torpedo per pylon. The torpedo project was a test concept only, this configurations wasn't used in battle.

Testing showed that it had a performance penalty of 16.7% with a top speed of 300 mph and a range of 1,000 miles. An alternate configuration was tested, where there was a single torpedo balanced by a 310 gallon drop tank. This configuration gave a performance penalty of 12.6% and an increased range of 2,160 miles.

Several factors contributed to the abandonment of this project, none of them being the satisfactory performance of the P-38F.

Several good sources for more information: United States Military Aircraft since 1909: Gordon Swanborough and Peter M. Bowers, Smithsonian Institution PressLockheed Aircraft Since 1913: Rene J. Francillon, Naval Institute Press

Great info re. torpedo testing, GG. Do you know maybe what was the take off power used on those tests? Any data about the date of the tests?
However, the British have contracted the Lightning II (= with turbos), but eventually they given up their order. Reason being the cost - the order for both the Lighting I and II was to be paid (cash carry), rather to be given under LL. For the Lightning I (and that one also had superchargers, two actually, but no two turbos, like the II), the lack of performance was also a contributing factor. The British have already purchased the B-17s with turbos, some were flying combat sorties as early as second half 1941 under RAF livery. They also purchased the B-24s with turbos.
USAF was more than happy to take over the order for the Lightnings.

To be honest, I didn't know the P-38F that was used for the testing was originally intended for the RAF...

I knew the first three sent to the RAF didn't have the superchargers on it (pre-war trade restrictions) and the RAF was less than impressed with them.

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My take from the Wikipedia article is that the Anglo-French Purchasing Committee intentionally ordered the P-38 sans turbochargers.
Is that incorrect?

From Wikipedia:In March 1940, the French and the British, through the Anglo-French Purchasing Committee, ordered a total of 667 P-38s for US$100M,[43] designated Model 322F for the French and Model 322B for the British. The aircraft would be a variant of the P-38E. The overseas Allies wished for complete commonality of Allison engines with the large numbers of Curtiss P-40 Tomahawks both nations had on order, and thus ordered the Model 322 twin right-handed engines instead of counter-rotating ones, and without turbo-superchargers.[44][N 3]

The excerpt is right on the money, but it lacks an important tidbit or two. The engines for the Model 322 were the same V-1710-33, a.k.a. C-15 engines, as installed on the P-40s contracted just before the 322s. Once the France fell, the British accepted the French part of the 667 contracted, but the complete contract was changed: only a few dozens will be built with C-15 engines without turbos, the rest (524 A/C) will be completed with F-5R/L (= handed, or opposite rotation) engines, and turbos. Seems like the Lockheed guaranteed 400 mph at 15000 ft for non-turbo A/C, and 415 mph at 25000 ft for turboed ones?
Once the 322s started arriving to the UK, and were fight tested, RAF felt that manufacturer promised what it was been unable to deliver. Ie. no 400 mph; though it would be interesting if someone is able to bring the test reports to the daylight. So the intended costumer stalled the things, and USAF stepped in, purchasing all the fighters that were stacking up in Lockheed's backyard, and whatever is going to be produced. The non-turboed ones were used mostly for training, and the armament was reduced in many of those down to 2 HMGs and 2 LMGs, since, without turbos the A/C were nose-heavy.
The high price might also be the problem, the contract was signed much before LL was introduced.

Yes. But I believe this was just the initial stage of testing when they were examining just weapons separation. I assume if they continued with the program they would have actually brought it down and ultimately over water.

I would guess that 12,000 feet would be a good altitude to release 1,900 pounds, not knowing how a sudden change in load/COG would affect the aircraft's handling: sudden nose-up attitude, violent yaw and so forth, giving enough height to either recover or bail out...

i would agree with that. just testing the drop and ac reaction after that. if that went satisfactory they would probably progress to dropping at actual attack height...which was like you said a hundred feet or so.